The present invention relates generally to power dividers, and more particularly, to a compact, ultrawideband matched E-plane power divider.
In order to achieve wide instantaneous bandwidth, transmission lines and other components of a corporate feed must be nondispersive, in that they must have negligible phase variations as a function of frequency. Parallel-plate waveguide is a TEM transmission line, and is nondispersive. Over-moded rectangular waveguide normally operates far from cutoff, so it is essentially nondispersive except at very low frequencies. Conventional E-plane bends, however, are dispersive due to the reactive characteristic of the T-junction.
The performance of E-plane T-junctions in conventional rectangular waveguide operating in the dominant TE.sub.1,0 mode is described extensively in the literature. For example, see C. G. Montgomery, R. H. Dicke and E. M. Purcell (eds.), "Principles of Microwave Circuits" (MIT Radiation Lab. Ser. No. 8), pg. 285, McGraw-Hill, New York, 1951, N. Marcuvitz (ed.), "Waveguide Handbook" (MIT Radiation Lab. Ser. No. 10), pp. 336-350, McGraw-Hill, New York, 1951, and T. Moreno, "Microwave Transmission Design Data", pp. 157-161, Artech House, Norwood, Mass., 1989.
Qualitatively, similar performance is obtained for E-plane T-junctions that operate in the TEM mode in parallel-plate waveguide, or if the sides are bounded by conducting walls, in the TE.sub.m,0 modes. Each of these junctions has a reactive component that produces a phase slope, or variations in the reflection and transmission phases, with changes in frequency. A tuning element such as a post or iris is typically used to cancel out the reactive component of the junction; however, due to the dispersive characteristic of the TE.sub.1,0 mode in rectangular waveguide, exact cancellation occurs at only one frequency with a residual phase slope elsewhere.
Accordingly, it is an objective of the present invention to provide for a compact, ultrawideband matched E-plane power divider.